The Kharaa and Yeröö River in Northern Mongolia form a part of the large Selenga River system which is the main tributary to Lake Baikal in Southern Siberia. With respect to Ecoregions the Yeröö is allocated to the Trans-Baikal conifer forests while most of the Kharaa belongs to the Daurian forst steppe. The river basins are covered by grassland/steppe and forest with the portion of rainfed cropland <10% . From the headwaters in the southeast, to the outlet in the northwest, the Kharaa and Yeröö Rivers cut across several major morphological and geological units and fault zones of the Mongol-Baikal Lake tectonic system. Stream landscape conditions range from close to pristine in their upper catchments, to rivers that are substantially affected by anthropogenic factors in their middle and lower reaches.